1. Field of the Invention
This invention generally relates to compositions of edible oils and phytosterol esters and the use of these compositions for preparing foods having cholesterol reduction characteristics. More particularly, the invention relates to compositions containing phytosterol esters for use as deep frying edible oils to prepare deep-fried food products that promote health and nutrition enhancement, including cholesterol reduction, when such deep-fried foods are consumed by living beings, especially humans.
2. Description of Related Art
Vegetable-based edible oils and compositions long have been used in baking, frying and food dressing applications. Edible oil products provide taste, nutrition and anti-stick properties for any number of pan frying, belt frying, baking, dressing or similar types of uses and applications. Edible oil products of this general type include liquid oils, cooking oils, margarines, whipped spreads, tub margarines, shortenings, oils, sprayable compositions, salad dressings and the like. These types of edible oil uses and applications can be categorized as edible oil compositions that are formulated to be used at relatively low temperatures and without substantial agitation. Such compositions are not suitable for so-called “deep frying” or “deep fat frying” applications.
In contrast, other edible oil components or compositions are provided that are suitable for such “deep frying” or “deep fat frying”. In deep frying applications, foods are fully immersed in the deep frying fat or edible oil which is at an elevated temperature suitable for such deep frying. Typical deep frying temperatures are at least about 350° F. (at least about 177° C.), often at least about 180° C. (at least about 356° F.). In addition, largely due to these relatively high temperatures and the content and temperature of foods that are deep-fried, deep frying conditions are under substantial agitation. In essence, deep frying “bubbles” the oil in association with air developed during heating. Thus, deep frying conditions are significantly harsher that the lower temperature uses noted above, such lower-temperature uses including pan frying and belt frying of foods such as potato chips.
Also contributing to harshness in deep frying operations is the make up of foods that typically are deep-fried. Many such foods are battered such as with bread crumbs, flour, spices, salt, egg and the like. Many frozen foods have ice crystals on their surface which adds water and volatility to the deep frying. All of these are extraneous to the food and to the oil, creating an oxidation environment that can be detrimental to food and oil quality. These extraneous materials can be considered “pro-oxidants” which catalyze, in the high temperature agitating environment of deep frying, undesirable break down of components in the oil. It has been found, in keeping with the invention, that such pro-oxidants will break down or damage phytosterols that are not chemically protected and/or dissolved in the deep frying oil. A discussion of oxidation in deep frying in the general context of oils and phytosterol fractions is found in Gertz et al., “Testing and Comparing Oxidative Stability of Vegetable Oils and Fats at Frying Temperature,” European Journal Lipid Science Technology, Vol 102, pages 543-551, 2000.
In the health, nutrition and metabolism art, publications suggest the usefulness of phytosterols in oil-based compositions. References which are in this general field include St-Onge, et al., “Consumption of a Functional Oil Rich in Phytosterols and Medium-Chain Triglyceride Oil Improves Plasma Lipid Profiles In Men,” American Society for Nutritional Sciences, 0022-3166/03, (2003), Journal of Nutrition, Volume 133, pages 1815-1820, (2003) reports a study evaluating the effects of a combination of medium chain triglyceride oil, phytosterols and flaxseed oil on plasma lipid concentrations and LDL particle size. Another article discussing plant sterols or phytosterols is St-Onge, et al., “Phytosterols and Human Limpid Metabolism: Efficacy, Safety and Novel Foods,” Lipids, Volume 38, No. 4, pages 367-375, (April, 2003). This article reports on studies regarding cholesterol-lowering efficacy of plant sterols with a view toward greater use of phytosterols in heart health promotion. These references, and each of the publications and patents noted throughout herein, are incorporated by reference hereinto.
References of Forbes Medi-Tech Inc also discuss phytosterol compositions. For example, Zawistowski et al., “Ruducol™-Cholesterol Lowering Functional Foods Phytosterols”, Innovations in Food Technology, May 2003, mentions clinical studies which show that phytosterol mixtures added to foods lower plasma LDL-cholesterol levels in humans. Stewart et al. U.S. Pat. No. 6,087,353 describes phytosterol compositions which are esterified and subsequently hydrogenated. These are said to be suitable for use alone or for incorporation into foods, beverages, pharmaceuticals, nutraceuticals, and the like. Zawistowski et al., International Publication No. WO 01/91587 describes oil compositions comprising short, medium and long chain triglycerides and the use thereof in reducing weight gain. Zawistowski et al. also discusses phytosterols, which incorporates phytostanols as noted therein. These phytochemicals are presently believed to have an ability to decrease serum cholesterol levels when fed to a number of mammalian species, including humans. Zawistowski et al. indicates that the relationship between cholesterol and phytosterol is apparently due in part to similarities in the respective cholesterol and phytosterol chemical structures. The mechanism set forth in references such as these is that phytosterols displace cholesterol from the micellar phase to reduce its absorption or compete with cholesterol in its absorption process.
Lottenberg et al., “The Human Cholesterol Ester Transfer Protein 1405V Polymorphism is Associated with Plasma Cholesterol Concentration and its Reduction by Dietary Phytosterol Esters”, American Society for Nutritional Sciences, 2003, indicates that margarine containing esterified polysterols lowers LDL-cholesterol without modifying HDL-cholesterol. Lea et al., “Safety Evaluation of Phytosterol Esters. Part 8. Lack of Genotoxicity and Subchronic Toxicity with Phytosterol Oxides”, Food and Chemical Technology, Vol. 42, pages 771-783, 2004, describes phytosterol esters modified to phytosterol oxides after heating. Perlman et al., U.S. Pat. No. 6,638,547, U.S. Patent Application Publication No. 2003/0096035 and U.S. Patent Application Publication No. 2005/0042355 describe converting non-esterified or “free” phytosterols to triglyceride-recrystallized phytosterols.
Nidishi et al. U.S. Patent Application Publication No. 2004/0156972 describes a non-deep frying cooking oil of triglyceride oil containing a plant sterol. Phytosterol esters are described in Wester U.S. Pat. No. 6,929,816 as texturizing agents in non-deep frying formulations incorporating hardstock oils.
Heretofore, it has not been appreciated that the combination of deep frying edible oil technology and phytosterol ester technology to provide deep frying compositions would be especially advantageously applied to the task of improving health by reducing undesirable cholesterol levels upon consumption of foods that have been prepared by deep frying in the deep frying edible oil composition. An especially important problem in this regard, which is addressed by the deep frying composition according to the invention, is to impart positive health attributes to deep-fried foods that otherwise may be perceived to have unhealthy attributes. The solution involves formulating deep frying compositions to favor transference of phytosterol esters to the deep-fried foods during the deep frying process itself.
The present invention substantially enhances deep-fried foods by incorporating phytosterols thereinto in order to thereby lower cholesterol levels in a subject by having the subject consume deep-fried foods. This is accomplished without degrading the flavor or other sensory attributes or the color of the deep-fried food products and without detrimentally affecting the frying or cholesterol-lowering performance of the deep frying composition. Also, substituting for a portion of the frying shortening potentially reduces some percentage of saturated fat consumed.